We are closing on our first South Bend rental property next week, as our local market opportunities have become non-existant unfortunately.  

Moreover, can you clarify if the complex is already an existing 16-unit or do you intend to build it?   

Used an existing frame down in Belize to build our house down there.  

Keep in mind this will be at a much higher rate than your current 3.2% interest rate, so I'm not sure if paying off the existing loan is a great choice.

As part of the project, the only existing drain on my side of the street is being sealed over with concrete and even that will be lost.

But I do have an issue with asking some of these pre-existing cabin owners to have to retrofit their cabin with the system and expecting them to have it done in a year or something. 

The existence of a contract -- I agree with you on this -- may be a complete defense to such a claim. 

You're increasing the need for hot and cold air dramatically and it's doubtful the existing system will be adequate.But, in answer to your original question - yes you will need a permit.

A cash purchase, added to my portfolio, reduces my levergage ratio on my real estate portfolio, but does not bring it to zero of course as I am not paying off existing low rate mortgages on rentals. 

What I typically see investors do to get rolling is use a Heloc or cashout refi on an existing property to get the startup capital they need.